LV11961HA Datasheet, PDF (9/14 Pages) ON Semiconductor – Single-phase FAN Motor Driver

LV11961HA
- PWM duty control
Duty of PWM output is determined by comparison of CPWM oscillation and DC level which is input to VTH
pin.
PWM output is in the mode of ...
Driving ( under the condition of CPWM > VTH )
Regenerating ( under the condition of CPWM < VTH )
The minimum duty of PWM output is determined by comparison of CPWM oscillation and DC level which is
input to RMI pin.
High duty of PWM output is determined by ...
VTH level ( under the condition of RMI > VTH )
RMI level ( under the condition of RMI < VTH )
That is, high duty of PWM output decreases only to the one which is determined by RMI level.
VTH
RMI
CPWM
2.15V(typ)
(=VREG x 69%)
0.62V(typ)
(=VREG x 20%)
OUT
Duty by RMI input
Controlled duty by VTH input
Fig.3
Full duty
- Soft switching
This IC operates to switch the driving phase of output softly by changing PWM duty gradually, which is
called Soft switching.
The term of Soft switching is 18.75% of FG half cycle each before and after the time of phase switching, as
shown in Fig.4 with details.
IN2
IN1
OUT1
OUT2
FG
TINH
TINL
Soft on
swi tch ing
PWM action
according to VTH level
Soft off
switchi ng
TINH x 18.75%
TINL x 18.75%
Soft on
swi tchi ng
PW M action
according to VTH level
Soft off
switchi ng
Soft on
swi tchi ng
TINL x 18.75%
TINH x18.75%
TINL x 18.75%
Fig.4
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